JPH0249052Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Field of industrial application The present invention relates to a hydraulic system for an agricultural tractor, and in particular to improvements to its hydraulic circuit.

(b) Prior art Conventionally, agricultural tractors in which a hydraulic pump and a hydraulic bubble are installed separately on the left and right sides of a transmission case, and the associated piping is connected with a transverse hydraulic pipe, are disclosed in Utility Model Application No. 53-87207 and Utility Model Application Publication No. 53-87207. As is already known from Publication No. 55-106012, etc., the relief bubble provided in the hydraulic circuit is provided in a location unrelated to the hydraulic pipe, and the return oil is sent to the rear transmission case outside the aircraft. It was brought back through a pipe installed in the

(c) Problems to be solved by the invention In the hydraulic system of the known tractor, the work of attaching the relief case to the fuselage and the work of attaching the pipe thereto are unstable and troublesome, and the work is performed by ejecting from the relief bubble. Since oil becomes hot, there were problems such as the oil temperature rising significantly if it was returned directly to the rear transmission case, which serves as an oil tank.

(d) Means for solving the problem The present invention is a tractor in which a hydraulic pump and a pressure oil extraction block are installed separately on the left and right sides of a machine body that has a transmission case at the front, and a hydraulic pipe is passed through the transmission case across the tractor. Connect the piping from the hydraulic pump to one end of the hydraulic pipe, attach a relief case that overlaps the pressure oil extraction block to the outside of the transmission case, and connect the pressure oil extraction block to the other side of the transmission case. communicating the inlet of the block with the hydraulic pipe;
The inlet of the relief case is made to communicate with the oil passage of the pressure oil extraction block, the outlet is made to communicate with the transmission case, and the transmission case 1 and the transmission case provided at the rear are connected through the oil passage. In addition to simplifying the installation, the return oil piping is omitted, and the temperature of the return oil from the relief bubble is reduced while flowing through the return path from the front transmission case. Solved the above problems.

(E) Example An example of the present invention will be explained with reference to the drawings.
Reference numeral 1 denotes a transmission case comprising a clutch housing 1a in which a main clutch 2, gears 3, etc. are housed, and a front transmission case 1b.An engine 5 is mounted on the front part of the transmission case, and a main shaft A rear transmission case 8, which also serves as an oil tank, is attached to the rear of the intermediate case 7, which houses the engine 6.
A transmission shaft 4 is installed in the intermediate case 7 so as to be in communication with bearings 7b, 7b before and after an oil pipe 7a contained therein.

10 is a brake pedal provided on the side of the operating deck 11, 12 is a handle, and a hydraulic lift cylinder 9a in a hydraulic case 9 provided at the upper part of the transmission case 8 is a lift arm 13 for raising and lowering the work machine. The front loader 15, which is provided at the front by tilting the loader 13 up and down, consists of a loader arm 15a and a loader bucket 15b, and is operated by a hydraulic system.

A hydraulic pipe 16 is provided in the transmission case 1.
is penetrated oil-tightly through an O-ring 19, and an oil feed pipe 18 of a hydraulic pump 17 provided on one side inside the bonnet is connected to one end of the pipe. It is connected to the outlet 21, and a pressure oil take-off block 22 is fitted on the other side, and a relief case 23 is superimposed on the outside of this pressure oil take-off block 22, and both are screwed to the transmission case 1.

The pressure oil extraction block 22 also has an oil port 25 that connects an oil pipe leading to the loader valve;
Oil passage 26 communicating with the inlet of relief case 23
and an oil passage 30 that communicates with the inlet 27 of the relief case 23, has an end connected to the return pipe of the loader valve, and has an oil port 28 in the middle that leads to the hydraulic case 9. , the return oil passage 32 of the relief valve 31 installed in the relief case 23 is connected to the front transmission case 1b.
Inside, the oil pressure take-out block 22 is connected to the front transmission case 1b through an oil hole 32a, and when the front loader 15 is not used, the oil port 2 is connected to the front transmission case 1b.
When the plugs 33 and 34 are screwed into the oil passage 30 and the oil passage 30 to close the valve, the hydraulic oil discharged from the right end of the hydraulic pump 17 via the oil feed pipe 18 and the hydraulic pipe 16 is transferred to the oil in the pressure oil take-off block 22. Hydraulic oil is pumped from the passage 26 to the oil passage 35 of the relief case 23, turns to the oil passage 28 through the outlet 27 and the oil passage 30, is discharged to the piping 29 connected to the outer end of the oil passage 28, and is discharged through the piping 29. is fed under pressure to a hydraulic lift cylinder 9a provided at the rear.

When using the front loader 15, remove the plugs 33 and 34, screw the elbows together, connect the oil supply pipe and return pipe to the loader valve, and install a spacer 30a with an O-ring in the oil passage 30. When inserted, hydraulic oil is sent from the oil port 25 to the loader valve, and return oil is sent under pressure from the oil port 28 to the hydraulic case 9 and the hydraulic lift cylinder 9a.

When the front loader 15 or the hydraulic lift cylinder 9a or the like is operated, and the load becomes larger than the set value of the relief valve 31, high temperature hydraulic oil is forced out from the relief valve 31, and this is transferred to the relief case 23. The hydraulic oil flows into the front transmission case 1b through the return oil passage 32, and this hydraulic oil accumulates in the front transmission case 1b to lubricate the transmission mechanism and also flows through the hole 3 bored in the rear wall.
7, flows backward through the bowl body 38, inside the pipe 36 in which the main shaft 6 is installed, and flows back into the rear transmission case 8 through the hole 40 of the bearing holder 39, during which time the temperature of the hydraulic oil decreases. However, the hydraulic oil in the rear transmission case 8 is sucked out from the suction port 21 by the hydraulic pump 17.

Note that return oil from the power steering valve 43 also flows into the front transmission case 1b and joins therewith.

Further, since the hydraulic pipe 16 crosses through the transmission case 1, the oil supply pipe 18, the pressure oil extraction block 22, and the relief case 23 can be easily installed by one person.

In FIG. 5, 42 is a position control valve, and 45 is a filter.

(g) Effects of the invention The present invention provides a tractor in which a hydraulic pump 17 and a pressure oil extraction block 22 are distributed and installed on the left and right sides of a machine body having a transmission case 1 at the front as described above. 16, and the piping from the hydraulic pump 17 is connected to one end of the hydraulic pipe 16, and on the other side of the transmission case 1, there is a pressure oil extraction block 22 and a relief case superimposed on the outside thereof. 23 is connected to the hydraulic pipe 16 at the inlet of the pressure oil extraction block, the inlet of the relief case 23 is connected to the oil passage of the pressure oil extraction block 22, and the inlet is connected to the transmission case 1. Since the transmission case 1 and the transmission case provided at the rear are connected through an oil passage, the relief case 23 is connected to the pressure oil extraction block 22.
It can also be easily attached to the end of the hydraulic pipe 16, and the return pipe from the relief valve 31 can be omitted. , returns to the front transmission case 1b and accumulates, flows and flows to the rear transmission case 8.
In the process of returning to normal condition, the oil temperature decreases and the hydraulic oil becomes hot, which can prevent various troubles from occurring.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention,
Figure 1 is a vertical cross-sectional view of a part of the transmission device of an agricultural tractor, Figure 2 is a cross-sectional view of the main parts, Figure 3 is a plan view of the agricultural tractor, and Figure 4 is a diagram of the pressure oil extraction block and hydraulic pipe. FIG. 5 is a cross-sectional view of the connection part, FIG. 5 is a cross-sectional view of the relief case and pressure oil extraction block, and FIG. 6 is a hydraulic circuit diagram. DESCRIPTION OF SYMBOLS 1... Transmission case, 1b... Front transmission case, 8... Rear transmission case, 16... Hydraulic pipe, 17... Hydraulic pump, 22... Pressure oil extraction block, 23... Relief case, 31 ……
Relief valve, 36...pipe.

Claims (1)

[Scope of utility model registration request] In a tractor in which a hydraulic pump 17 and a pressure oil extraction block 22 are installed separately on the left and right sides of a machine body having a transmission case 1 at the front, a hydraulic pipe 16 is installed in the transmission case 1 by passing through the hydraulic pipe 16. A pipe from the hydraulic pump 17 is connected to one end, and a pressure oil take-off block 22 and a relief case 23 superimposed on the outside thereof are attached to the other side of the transmission case 1, and the flow of the pressure oil take-off block is controlled. The inlet of the relief case 23 is communicated with the hydraulic pipe 16 at the inlet, the inlet of the relief case 23 is communicated with the oil passage of the pressure oil take-off block 22, the inlet is communicated with the transmission case 1, and the transmission case 1 is connected to the transmission case 1 and the transmission case 1 provided at the rear. A hydraulic system for an agricultural tractor, characterized in that a cylinder case is connected through an oil path.